package org.bouncycastle.asn1;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.Enumeration;

public class DERSequence extends ASN1Sequence {
    /**
     * create an empty sequence
     */
    public DERSequence() {
    }

    /**
     * create a sequence containing one object
     */
    public DERSequence(DEREncodable obj) {
        this.addObject(obj);
    }

    /**
     * create a sequence containing a vector of objects.
     */
    public DERSequence(ASN1EncodableVector v) {
        for (int i = 0; i != v.size(); i++) {
            this.addObject(v.get(i));
        }
    }

    /**
     * create a sequence containing an array of objects.
     */
    public DERSequence(ASN1Encodable[] a) {
        for (int i = 0; i != a.length; i++) {
            this.addObject(a[i]);
        }
    }

    /*
     * A note on the implementation: <p> As DER requires the constructed,
     * definite-length model to be used for structured types, this varies
     * slightly from the ASN.1 descriptions given. Rather than just outputing
     * SEQUENCE, we also have to specify CONSTRUCTED, and the objects length.
     */
    @SuppressWarnings("rawtypes")
    void encode(DEROutputStream out) throws IOException {
        // TODO Intermediate buffer could be avoided if we could calculate
        // expected length
        ByteArrayOutputStream bOut = new ByteArrayOutputStream();
        DEROutputStream dOut = new DEROutputStream(bOut);
        Enumeration e = this.getObjects();

        while (e.hasMoreElements()) {
            Object obj = e.nextElement();

            dOut.writeObject(obj);
        }

        dOut.close();

        byte[] bytes = bOut.toByteArray();

        out.writeEncoded(SEQUENCE | CONSTRUCTED, bytes);
    }
}
